Process for rendering celluloid uninflammable and incombustible.



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PROCESS FOR RENDEBING CELLULOID Specification of Letters Patent. I Application filed April 18, 1907. serial No. 368,988.

To all whom it may concern: Be it known that I, PASCAL MARIN-o, chemist,'a sub'ect of the King of Italy, and residing at 6 eatherstone Buildin s, High Holborn, Vi". C., in the count land, have invented an mproved Process for. Rendering Celluloid Uninfiammable and Incombust-ible, of which the following is a specification.

This invention relates to a recess having for its ob'ect to. render cellu oid uninflammable an incombust-ible while at the same time preserving the transparency, stren th, and elasticity of ordinary ce uloid. {or this purpose ordinary celluloid that is cellulose compounded with 'cam her or its is dissolved in a c osed vessel by means of suitable solvents, such as acemethyl-alcohol, acetic acid mixed with acetic anhydrid and absolute alcohol, alcoholic ether, ethvl acetate, or amyl acetate. This solution of celluloid must have a certain degree of density, not too dilute nor too viscous. If it is too dilute it will become concentrated when exposedior some time to the open air, small uantity of solvent used may be added. T e followin liquid is then sepprately made up to be ad ed afterwards to t e-solution of celluloid thus obtained;

One or more mineral salts, not soluble either in cold water, boiling water or alcohol (but which are soluble in acetic acid with or without an admixture of acetic anhydrid) is or are dissolved in suflicient acetic acid,

with or without acetic anhydrid to produce the solution of the salt or salts taken. This solution is then filtered. The proportion of the salt; or salts, used should be from two to three parts by weight of salt, or salts, to from ten to fifteen parts by weight of dissolved celluloid or thereabouts. a

The above mentioned mineral salts not soluble either in cold water or in boiling water or alcohol, but which are soluble in acetic acid and acetic anhydrid, are twentyfour in number and are well known but for the sake of convenience they may be specified as follows:-(1) Aluminium hydroxid. (2) Aluminium iodid. (3) Barium chromate. Barium tribasic phosphate. pyrophosphate. (7) Calcium arscnate.

"alciuxn arsenite.

(10) Calcium tribasic phosphate (11) (hromium oxid. (l2) OR MlSSlN itscn MAKING, OF LONDON, ENGLAND.

of ondon, Engj while if itis too thick a (4) Barium dibasic phosphate (5) (9) Calcium basic phos-' Nib/i921 'U'NWFLAMMABLE INCOMBUSTIB'LE.

Patented July 21, 1908.

Cobalt phosphate. (13) Iron .phos hate (ferric) (14) Iron phosphate (ferrous) (15) 'Iron pyrophosphate (ferric) (16) Lead fiuorid. (17) Lead nitrite basic. '18) Magnesium pyrophosphate. (19) Niikel phosphate. (20) Silver arsenate. (21) Silver' phosphate. (22) Silver pyrophosphate. (23) Sodmmiperiodate. (24) Stannic acid;

The choice of the salts must be made with discrimination according to whether it is desired to make the uninflammable celluloid transparent or shaded in very delicate tints. It should be remarked in this connection that aluminium hydroxid, barium phosphate, calcium phosphate and magnesium pyrophosphate, give no shade to the non-inflammable celluloid which consequently remains as transparent as ordinary celluloid, but by using barium chromate, or chromium oxid a tint can be obtained varying from and s ades' possessing the brilliancy of mother-of-pearl are obtained by a suitable mixture 0 nickel phosphate, cobalt phosacid and lead fluorid, and lead nitrite basic. To the vsaid solution of salt or salts is afterwards added carbon tetrachlorid, which is a colorless liquid insoluble in water but soluble in alcohol and ether. This liquid may be replaced byfcarbon tetrabromid, but the latter is objectionable commercially owing to its high price. The proportion of the carbon tetrac lorid used should be from three to five parts by weight of the same to one hundred parts by weight of dissolved celluloid or thereabouts. There is also afterwards added to the aforesaid mixture some chloro picrin known under the name of trichlor-nitromethane C(NOQCl which is a colorless noncombustible liquid, and (C N,) which is also uninfiammable, and insoluble in water but soluble in alcohol and ether. The proportions preferably used being from 3 to 5 arts by weight of each to 100 parts by weig t of dissolved celluloid or thereabouts. The whole mixture as '.bove described is now added to the dissolved celluloid in the closed vessel and 1s thoroughly mixed and exposed for 5.0m ten to twelve hours in the said closed vessel to the action of the ingredients and their vapors. After this process there is finally added a small quantity of formaldehyde solution the whole mixture being thoroughly stirred in the closed vessel, and the celluloid is then straw ellow. to the shade of maize.- Tintsphate, ferric and ferrous phosphates, stannic We, 6 -----U mm.) STATES PATENT OFFICE.

SEARCH ROOM:

some cyanogen again exposed to the action of the vapors of the formaldehyde, which are not mflammabl for from ei ht to ten hours. Owing to the ac tion-of the so ution of formaldeh de, the formaldehyde which is of the methyhc series combines all the molecules of the celluloid in solution and makes one body. The water which is in the formaldehyde is absolutely I so refractory and does not combine with the cellu' oid thus the celluloid agglomerates inone piece and floats in theaqueous hquid. The celluloid agglomerates or gathers together so as to form acompact mass floating upon-the-liquid. The whole of this 1i uid is then drawn off, and the remaining ce uloid" .paste is dried, rolled, and molded to the redissolvin the celluloid by any suitable solvent, suc as those herein described, addiu to the dissolved celluloid one or more mineral salts (insoluble in cold or hot water or alcohol, but soluble in acetic acid or acetic anhydrid) the said salt or salts being dissolved in acetic acid or acetic'anhydrid or a mixture of both, afterwards addin carbon tetrachlorid, or carbon tetrabromi and a ain adding trichlor-nitro-methane C(NO,) 1,, and cyanogen (C N thoroughly mixing and exposing the admixture m a closed vessel to the action of the ingredients and their vapors for from twenty to twent yfour hours, again adding to the compound formaldehyde solution, thoroughly mixing and again exposin the. said mixture or compound in the close vessel for a further period of from eight to ten hours and finally drawing off the lkhuid from the resulting-compact mass of ce uloid and drying'the'latter which may then be rolled or molded as desired all substantially as described and in or about the proportions named.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

1 PASCAL MARIN O. Witnesses Fnansmcx Mrom MELLOR, -Jpnn Jam-2s RAWLEY. 

